Fabric tensioning device for knitting machines and method



May 29, 1962 P. ST. PIERRE ET AL 3,036,449

FABRIC TENSIONING DEVICE FOR KNITTING MACHINES AND METHOD Filed April 12, 1955 5 Sheets-Sheet l May 29, 1962 P. 51. PIERRE ET AL 3,036,449

FABRIC TENSIONING DEVICE FOR KNITTING MACHINES AND METHOD Filed April 12, 1955 5 Sheets-Sheet 2 I I I 4 I a I ,9 4 I I I a,

May 29, 1962 P. 1.. s-r. PIERRE ET AL 3,036,449

FABRIC TENsIoN Nc DEVICE FOR KNITTING MACHINES AND METHOD Filed April 12, 1955 5 Sheets-Sheet 3 May 29, 1962 P. L. ST. PIERRE ET AL FABRIC TENSIONING DEVICE FOR KNITTING MACHINES AND METHOD Filed April 12, 1955 5 Sheets-Sheet 4 Ha. I!

INVENZ'OIE s paw/52w Wm y 1962 P. ST. PIERRE ET AL 3,036,449

FABRIC TENSIONING DEVICE FOR KNITTING MACHINES AND METHOD Filed April 12, 1955 5 Sheets-Sheet 5 3,036,449 FABRIC TENSIONING DEVICE FOR KNITTING MACS AND METHOD Paul Leo St. Pierre, Pawtucket, Joseph Wawzonek, Cumberland, and Eugene St. Pierre, Pawtucket, R.I., assignors to Hemphill Company, Pawtucket, R.I., a corporation of Massachusetts Filed Apr. 12, 1955, Ser. No. 500,756 26 Claims. (Cl. 66-150) This invention relates to an improvement in fabric takeup or draw-off devices for knitting machines. It will be described as applied to a circular, independent needle, hosiery knitting machine for the manufacture of ladies sheer inturned welt nylon hosiery, but it is not intended to thereby limit the use or scope of the invention thereto.

It is well known that, in order to obtain the desired size, the welt of a ladies seamless nylon stocking must be knit as loosely as possible. It is equally well known that the extremely smooth and slippery nature of nylon yarn, particularly in the finer deniers, makes it extremely difficult to obtain clear and uniform fabric, particularly in the welt which, because of its lightness, does not readily flow downwardly into the cylinder, but tends to bunch up into a rather tight wad adjacent the knitting level, and this results in distortion of the knit-ted loops producing what are commonly called crows feet, which seriously impair the appearance of the fabric.

Various mechanical expedients have been used, with more or less success, to guide the fabric of the welt away from the knitting needles and down into the cylinder until a sufiicient length has been knit to permit connection to a mechanical takeup or draw-01f mechanism of some sort. It has also been suggested that the fabric be caused to move away from the needles and downward towards the cylinder by impingement of a jet of air upon the fabric adjacent the knitting point. This method may be an improvement over those employing mechanical devices in some respects, but is wholly ineffective to rna1'n tain adequate tension upon the fabric throughout the knitting of a stocking so that, as far as is known, air has been used only as a means of causing knitted fabric to become engaged with a mechanical takeup after the welt fabric has been completed and the welt turned.

It is also a well known fact that, because of the necessity of departing from a strictly tubular shape through the formation of heel and toe pockets, a mechanical takeup is incapable of maintaining a uniform tension all the way around a stocking throughout its production and, to compensate for this, various forms of heel and toe pocket spreaders have been used to apply localized tension to the fabric in the longitudinal areas occupied by such pockets. All of this is cumbersome, complicated, and expensive.

By this invention, air may be caused to fiow over all parts of the upper edge of the cylinder and to impinge upon the fabric from the beginning of the initial course to the completion of the stocking in such a way that, although the fabric hangs and turns free of external weight, an adequate amount of friction on the fabric is produced to cause it to move smoothly away from the needles as the loops are knit, and to maintain an adequate tension upon all parts of the fabric, regardless of heel and toe pockets, throughout the knitting of the entire stocking so that the fabric, regardless of its length, is substantially uniformly stretched, and not only is initial bunching eliminated but the Wale-wise structure of the fabric materially improved. One way to describe the operation of this take-up is to say that the air current entrains the fabric hanging from the needles. A column of air moving down through a fabric work tube exerts a drag upon the fabric and stretches it away from the needles dur- 1:. a v Patented M y 1962 ing the knitting process. This stretching or tensionirrg acts as a weight upon the knitted fabric to hold the individual loops thereof under stress during, and subsequent to, the knitting operation. This results in a more flaw-free and uniform fabric because it prevents the knitted product from bunching and rubbing on itself and holds each loop to size after it has been knit.

One of the recognized differences between the usual seamles and full fashioned stocking has been that, in the latter, the needle wales are considerably more conspicuous than in the former. This distinction is largely eliminated by this invention. Furthermore, the invention is applicable to any standard circular hosiery knitting machine without difiiculty or alteration of any of the usual parts or adjustments and is extremely simple, reliable and much less expensive than the mechanical devices which have been considered necessary if the best possible fabric is to be obtained.

One form of the invention is shown in the drawing, of which:

FIGURE 1 is a front view of part of a circular knitting machine embodying the invention;

FIGURES 2 to 7 are detailed views of parts of the same device;

FIGURES 8 and 9 are end and front elevations, respectively, of a receiving receptacle with automatic stocking discharge whereby the device is rendered entirely automatic;

FIGURES E10 and 11 are views of another form of automatic discharge device;

FIGURE 12 illustrates a means of cutting off the suction Without stopping the suction fan; and

FIGURES 13-14 show other embodiments of the invention.

As best shown in FIGURE 1, the interior of the cylinder 1, which is assumed to be the cylinder of a circular, independent needle, knitting machine for the knitting of ladies nylon hosiery, is provided with a tube 2 of plastic or any other suitable material, preferably of an internal diameter as small as practicable. This tube is centrally positioned Within the cylinder and extends straight downwardly as far as necessary to accommodate a complete stocking, as shown in FIG. 1. Thereafter, the tube may be looped as shown in FIG. 1 to terminate in a receptacle 3 at a convenient height for the machine operator. The other end of receptacle 3 connects with a tube 4 which, in turn, connects with the intake of a suction fan 5 which may exhaust into the air, or, preferably, into a porous bag 6 (FIG. 9) similar to that commonly used in small vacuum cleaners.

As shown in 'FIG. 4, the upper end of tube 2 preferably terminates in a close fitting sleeve 7, the upper end of which is flared outwardly to make a relatively close fit with the upper end of the cylinder and yet permit free rotation of the cylinder.

Seamless hosiery of the type referred to is usually knit by a machine having a dial such as that indicated at 8 in FIG. 4. In consequence, the flow of air resulting from the reduction of pressure within the tube 2 by suction fan 5 is restricted substantially to the narrow annular space between the lower edge of the dial and the upper edge of the cylinder. All around this space, the air will flow inwardly and downwardly with substantial uniformity and, depending upon the size of the tube 2 and the power of fan '5, will apply friction to the knitted fabric not only to cause it to move downwardly into the cylinder but to tension it irrespective of its increasing length. If it is found that the increase in tension resulting from the in creasing length of fabric has appreciable effect upon the length of the knitted loops, this can be compensated for by the stitch length adjustment which is a part of all machines of this type.

Stockings of this kind are customarily knitted individually, each being run off the needles before the 'next is begun. When this occurs, the finished stocking will be sucked through the tube 2 and into the receptacle 3 from which it can be removed by the operator at any desired time.

To keep the stocking from being pulled into the fan, a perforated bafile 9 is interposed. As shown in FIG. 2, this may be positioned adjacent the end of receptacle 3 to which the fan 5. is connected and, preferably, at an angle similar to that shown so that the stocking will tend to drop to the bottom of receptacle 3, from which it will fall when the receptacle is opened.

Receptacle 3 maybe of any desired type. That shown in FIGURES 1, 2 and 3 consists of a cylindrical housing somewhat larger than tube 2 and having a substantially semicircular opening in its lower half. This housing is surrounded by a similar sleeve 10 having a similar opening adapted to register with that of the first mentioned housing and which is turnable thereon so as to form a closure for the receptacle. It is shown open in FIG.

2 and closed in FIG. 3.

In knitting an inturned welt, the initial courses are suspended from bits in the dial and the knitting continued upon the cylinder needles until the welt is completed, afterwhich the loops upon the bits are transferred to the cylinder needles to turn the welt. In consequence, during the knitting of the welt, the fabric is in the form of an annular pocket between the two sides of which the air enters. This tends to press that part of the fabric which is in contact with tube 2 so tightly against the tube that it may not slide readily down into it. Also, with certain atmospheric conditions, this tendency may be aggravated by the creation of static electricity.

However, this may be, it has been found desirable to prevent too close contact between the fabric coming off the cylinder needles and the upper end of sleeve 7 so that aircan get between the 'fabric and the tube as well as inside of the fabric pocket. To this end, the upper end of sleeve 7 is provided with'a number of inwardly projecting arches 11 which may be of plastic or wire or other suitable material rigidly attached to the flared end of the sleeve and extending diagonally downwardly within the sleeve to below the junction between the flared end and the sleeve proper, the diagonal slope corresponding to the direction of the rotation of the cylinder so that arches 1'1 serve not only to keep the fabric from too close contact with the sleeve and admit air between the fabric and the sleeve but also tend to cause the fabric to move downwardly in substantially the same manner for which metal fins have been employed in the past.

Receptacle 3, as shown in FIGURES 2 and 3, requires manual operation to remove a stocking. If desired, the operation may be made fully automatic either by opening and closing sleeve 10 by suitable mechanical means, or

by modifying receptacle 3 as shown in FIGS. 8 and 9..

In these figures, sleeve 10 is eliminated and its place taken by a cover 12 also adapted to close the opening in receptacle 3. In this case, however, the cover 12 is attached at one edge to a rotatable shaft 13 mounted in suitable brackets 14 which may also serve to support receptacle 3 and to one end of which is affixed a crank 15. This crank is connected through a link :16 to a lever 17 rigidly attached to a rocker 18. Rocker 18 is arranged to ride upon a drum 19 which may be fixed to the usual drum shaft, of the machine and in alignment with one. or more'cams 20 so that, when rocker 18 rides up on one of these cams, cover 12 will be swung open and will be closed again by means of a spring 21 when cam 20 moves from under rocker '18.

Since thesuction of fan is likely to hold the stockin; in receptacle 3 tightly against baffle 9, there is also provided a switch 22 in the electric circuit of fan 5 so that, when lever 17 moves to open cover 12, it will also cause the switch 22 to break: the circuit, and will com:

l plete the circuit again when it moves back to it s normal" position.

The switch shown is of common push type whichmay be operated by this sort of mechanism without ditficulty.-- In this way, the dropping of the stocking from the sea ceptacle into a suitable receiving container below it, such' as that shown at 23, is effected automatically and is unimpeded by the suction which has been momentarily eliminated.

Another type of receptacle is shown in FIGURES l0 and 11. This is shown as having the same diameter as tube 2. Housing 24 is cut away to provide a downwardly directed discharge opening of considerably more than half the circumference of the receptacle, leaving a relatively narrow strip 25 at the top which serves to connect the two cylindrical ends of the receptacle, one of which connects with tube 2 and the other with fan 5 as in the other form.

The discharge opening is closed by two opposed swinging doors 26 and 27. Door 26 is fixed to rod 30 by brackets 28 and door 27 is fixed to a similar rod 31. Rod 30 is rotatably mounted in fixed posts 32 and 33, and rod 31 is similarly mounted on the same posts. Fixed to rod 31 is crank 34. Also fixed to rod 31 is another crank 35. Fixed to rod 30 is crank 36. Cranks 35 and 36 are connected by a link 37. Cranks 34, 35, and 36 and link 37 are so arranged in proportion that, if crank 34 is swung forward (to the left in FIGURE 10), door 27 will be swung back and door 26 will be swung forward, as shown in dotted line in FIG. 10, so that the opening in the receptacle is unobstructed and the stocking which has reached the receptacle is free to drop out if the suction is cut olf.

Crank 34 is reciprocated by a lever 38 attached to a rocker 39 adapted to be rocked by a cam or cams 40 upon drum 41. The connection between crank 34 and lever 38 is made by collars 42 and 43 -upon a rod 44 which is pivotally attached to lever 38 as at 45. By means of collars 42 and43, the relation between lever 38 and crank 34 may be varied to meet the operating requirements of the doors. The doors may be made substantially air-tight by suitable sealing strips upon 01' adjacent their edges and the edges of the receptacle.

The suction may be automatically stopped by a switch 46 also operated by lever 38 so that the circuit of the suction fan may be broken as the doors are opened or, if desired, before or after this occurs.

From the viewpoint of motor durability, it may be de-, sirable to permit continuous operation of the motor and suction fan and to cut off the suction from the receptacle by a suitable valve. In FIGURE 12, a simple butterfly valve 47 is shown mounted in the tube which connects the receptacle with the fan. Crank 48, operably connected to a lever 49 attached to lever 38 as at 50, indicates a suitable means for operating valve 47 so that the connecting tube between the receptacle and the fan will be closed and the receptacle freed of suction at the desired time.

The invention has been explained in its preferred embodiment wherein the use of a mechanical takeup is entirely eliminated. It may, however, be used in conjunction with a mechanical takeup such, for instance, as the well-known cup and cap arrangement disclosed originally in US. Patent No. 2,230,974 which issued to Augustin Gagne and in a later modification in US. Patent No. 2,625,026 issued to Robert H. Lawson.

FIGURE 13 shows such a takeup, employing a cup 51 and a cap 52. The cup is rotatably supported on a shaft 53, and the cap is likewise rotatably supported on another shaft 54. The shaft 54 which is concentric with the shaft 53 is hollow and adapted to be connected to an air suction system. This system causes a current of air to flow into the cup and through holes 55. When the cup, thus connected to a suction system, is moved to the top of a needle cylinder, the air current into the cup will entrain and drag with it the fabric coming from the needles, thereby preventing it from bunching up and placing it under tension. After the turning of the welt has been completed and the held loops have been transferred from the dial bits, the cup is closed by the cap and the entire assembly acts as a fabric tensioning weight throughout the knitting of the rest of the stocking. The above identified patents may be referred to for a more detailed description of how this mechanism may be operated.

FIGURE 14 shows a modification of the fabric receiving tube which extends concentric With, and down through the inside of, the needle cylinder. This modification consists of a tube 56, similar to tube 2 in FIG. 1, leading to a larger tube 57. This is one method of providing a tube which is relatively small at the top and larger below. Its purpose is two-fold.

First, it provides for a greater suction and, consequently, a greater tension on the fabric while the stocking is in its earlier stages of formation and the welt is in the upper or smaller portion of the tube. As more fabric is produced and the stocking lengthens, the tension increases and, consequently, a greater drag is produced on the fabric. Providing a Wider portion below lessens the tension while the lower part of the ankle and calf are being knit so that the stitches are tighter and assist in the fashioning of the stocking.

The second advantage of the larger tube is that it lessens the liability that the stocking will twist upon itself as it lengthens due to greater frictional resistance of the Welt which is bulkier than the rest of the fabric. The larger portion of the tube permits the welt to turn freely.

The tube may be widened at any suitable spot along its length depending upon requirements of the user. When knitting average ladies hose, the wider portion may be satisfactorily started at approximately 1% feet below the top of the cylinder.

The standard fashioning mechanism which increases or decreases the length of draw of the stitch by manipulating either the cylinder or the stitch cams produces a satisfactory fabric. The method of fashioning explained above is best used as an adjunct to the standard methods.

Another Way of using the suction produced air current for fashioning purposes is to provide an automatically operated air vent in the suction tube. This vent can be opened or closed in varying degrees by a pattern control mechanism to diminish or increase the amount of air flowing in at the top of the tube, thereby increasing or decreasing the amount of tension on the fabric.

This invention also can be used to assist or eliminate the function of the sinkers in knitting. If a sufliciently strong suction is used, it will place the fabric under enough tension to *aid the needles in casting off their stitches and eliminate the necessity of using sinkers for this purpose. If, then, the stitches are drawn over the walls of the cylinder or a stitch forming insert placed at the top of the cylinder, hosiery fabric can be knit without the aid of sinkers.

Sinkerless knitting has been accomplished on body machines and hosiery machines, chiefly of the hand operated stationary cylinder type. The body machines, however, have required a very strong mechanical takeup to accomplish this result; and the hand machines have used heavy weights for straightaway knitting and additional, manually applied, Weights during the knitting of heel and toe pockets and the fabric immediately following them. The suction mechanism described herein can take the place of these mechanisms and weights; and, if desired, air jets can be used to assist or in lieu of suction, especially during the knitting of the heel and toe pockets.

It is to be understood that any suitable kind of vacuum or air displacement system may be substituted for that shown and described. Similarly, although the invention has been described as applied to a single machine, it is to be contemplated that a central suction system can be used for a number of machines, and that these machines for delivering completed articles of knitwear to a central inspection area. If this were done, the articles could be stitch coded in some way to identify each one with the machine which produced it.

Although the invention has been described as applied to a ladies hosiery machine knitting plain fabric, it can also be used on other circular machines producing mens hosiery or other types of knitted fabric. It can also be used on twocylinder or dial and cylinder machines which produce rib fabric. In fact, it is not to be limited to merely circular machines; but, with an appropriately shaped fabric receiving tube, it can be applied to V- bed and other types of machines.

We claim:

1. A method of knitting fabric on a circular knitting machine having a needle bearing cylinder which includes knitting the fabric with the needles of the cylinder and providing an air current down through and substantially concentric with said cylinder adapted to entrain and tension the fabric as it is knit.

2. A method of sinkerless knitting which includes the steps of raising needles to take yarn in their hooks, lowering the needles to form loops of yarn over fixed loopforming members and simultaneously pulling said loops through previously formed loops sliding up on the shanks of the needles, and then casting these previously formed loops off of the needles with the aid of an air current which entrains and tensions the fabric as it is knit.

3. In a circular knitting machine having a cylinder provided with knitting needles adapted to be operated to produce knitted fabric, means for producing down through and substantially concentric with said cylinder a current of air while the fabric is being knit to hold the fabricunder a condition of substantially constant tension.

4. A fabric tensioning device for a circular knitting machine having a needle bearing cylinder which comprises a fabric receiving tube substantially concentric with said cylinder and means for producing down through and substantially concentric with said tube a current of air adapted to entrain and thereby tension said fabric as it is knit.

5. A knitting machine having a needle bearing bed, a fabric receptacle, and a fabric receiving tube interior of and concentric with said bed, said tube leading from said bed to said fabric receptacle, and means for creating a current of air concentric with said tube to said receptacle adapted to entrain and tension fabric as it is being knit.

6. The invention according to claim 5 and wherein said receptacle has a closure member adapted to be opened for the purpose of removing a knitted article.

7. The invention according to claim 6 and wherein said means for creating a current of air comprises a motor driven, air displacing, device beyond said receptacle.

8. The invention according to claim 7 and wherein there is provided a fabric container adjacent said receptacle and means for moving a knitted article from said receptacle to said container.

9. The invention according to claim 8 and wherein said means for moving includes means for opening said closure member and for interrupting said current of air.

10. A method of producing fabric which includes the steps of looping yarn into a fabric with knitting needles and drawing the knitted fabric from the needles by means of an air current under suction.

11. A method of producing tubular fabric which includes the steps of forming the fabric from one or more individual yarns and drawing the fabric from the fabric forming means as it is formed by entfaining it witha current of air under suction.

12. In a circular knitting machine havinga needle bearing cylinder, a plurality of needles carried by said cylinder, means for feeding yarn to said needles, and means for operating said needles so as to knit loops of man...

said yarn to form a fabric, means comprising a suction producing device for pulling said fabric away from the needles as it is knit and holding it under tension.

13. In a circular knitting machine having a needle bearing cylinder, a fabric tensioning device which cornprises suction means for producing an air current within said cylinder to entrain said fabric as it is knit.

14. The invention according to claim 13 and wherein said suction means includes a fabric receiving tube and a motor driven air displacing mechanism.

15. In a circular'knitting machine having a needle cylinder, a fabric receiving tube concentric with said cylinder with one end proximate the top of said cylinder, and means at the other end for producing a suction within the tube to hold knitted loops of fabric produced on the needles of said cylinder under a condition of tensioned stress While the fabric is suspended from the needles during the knitting process.

16. The invention according to claim 15 and wherein means is provided for delivering a knitted article from said tube to a fabric container.

17. The invention according to claim 16 and wherein said means for delivering a knitted article includes an opening in said tube and a removable covering for said opening.

18. The invention according to claim 17 and wherein means is provided for eliminating the suction in said tube when said covering is removed.

19. The invention according to claim 15 and wherein said fabric receiving tube has variations in its inside diameter.

20. The invention according to claim 19 and wherein said'tube has a bottom portion of greater diameter than itstopportion. a

21. In a circular knitting machine having a frame, a needle supporting cylinder, a plurality of needles slidably mounted in said cylinder, a plurality of dams adapted to operate said needles, and means for feeding yarn to the needles, a fabric receiving tube disposed centrally of said cylinder, with an open end proximate said needles,

and means for producing a suction atsaid end of said tube to entrain and tension fabric as it is produced.

22. A fabric tensioning device for a circular knitting machine having a needle bearing cylinder which comprises a fabric receiving member, suction means for bringing knitted fabric into contact with said receiving member, and a fabric clam ing member adapted to hold the fabric in its position of contact with said receiving member.

23. For a circular knitting machine having a needle bearing cylinder a fabric receiving device which comprises hollow fabric receiving tube interior of and concentric with said cylinder, the top of the tube being adjacent the top of the cylinder and being provided with at least one diagonally disposed, inwardly projecting, fabric-lifting member, said member having an air passage through its body to permit an air current to pass through it to lift the fabric from the surface of the tube and means for pro viding such an air current.

2 4. 'In a circular knitting machine having a needle bearingcylinder and means for producing knitted fabric and feeding it within said cylinder, air discharge means for producing down through and substantially concentric with said cylinder a current of air adapted to entrain and tension said fabric as it is knit.

25. A method of producing fabric on knitting needles which includes looping the yarn into a fabric with the needles and holding the fabric, as it is produced, under tension by means of a suction produced air current adapted to entrain the 'body of the fabric with sufficient force to hold the individual loops thereof under stress.

26. In a circular knitting machine having a needle cylinder, needles movable in said cylinder and means for actuating the needles to produce a knitted fabric adjacent one end of said cylinder; means for taking up the fabric as it is knit comprising suction means for inducing a flow of air through said cylinder from said end.

References Cited in the file of this patent UNITED STATES PATENTS 2,020,694 Mauritsch et al. Nov. 12, 1935 2,275,276 Williams Mar. 3, 1942 2,405,162 Nyhuis Aug. 6, 1946 2,408,807 Norman Oct. 8, 1946 2,422,514 Allen June 17, 1947 2,485,230 Alexander et al. Oct. 18, 1949 2,636,364 Moss Apr. 28, 1953 2,644,325 Home et al; July 7, 1953 2,694,304 Butler Nov. 16, 1954 2,709,352 Lawson May 31, 1955 2,729,082 Tew Jan. 3, 1956 

